Fiber optic phototherapy devices including LED light sources

ABSTRACT

Fiber optic phototherapy devices include fiber optic light emitters having fiber optic end portions at one or both ends that may be separated into a plurality of groups of end portions that receive light from one or more light emitting diodes (LEDs). Lenses may be used to focus the light from one or more LEDs onto the end portions. The LEDs may be mounted to a heat sink to dissipate any excess heat generated by the LEDs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.10/919,884, filed Aug. 17, 2004.

FIELD OF THE INVENTION

This invention relates to phototherapy devices including fiber opticlight emitters that receive light from one or more light emitting diodes(LEDs).

BACKGROUND OF THE INVENTION

Phototherapy has long been used to treat various known conditionsincluding, for example, jaundice in newborn infants. Jaundice is causedby a build up of bilirubin in the blood of infants. Exposing theinfant's skin to certain types of light will quickly reduce thebilirubin to a safe level. Such treatment is generally only needed for afew days, until the infant's liver is mature enough to process thebilirubin.

One type of phototherapy device that is commonly used in phototherapytreatment comprises a fiber optic light emitter having fiber optic endportions that receive light from a halogen lamp or other relatively highwattage light source to obtain the desired amount of light output fromthe light emitter. The problem with using relatively high wattage lampsas the light source is that they are not very efficient and producelarge amounts of heat that require the use of a fan to cool the lightsource. Incorporating a fan into the light source makes the light sourcequite noisy during operation and substantially increases the overallcost and size of the light source. Also such relatively high wattagelamps typically have a relatively short life and provide less light overtime.

A need thus exists for a fiber optic phototherapy device that may belighted by a light source that requires considerably less wattage tooperate while still producing substantially the same amount of lightoutput from the fiber optic light emitter for a given unit surface area.

A need also exists to be able to selectively light different segments orareas of a fiber optic light emitter at the same or different times asdesired to allow the light to be turned off to different segments orareas if not needed. This not only saves on power, but may also reducethe amount of light to which care providers are exposed. Some careproviders are very sensitive to certain bands of light, particularlyblue bands which are especially effective for phototherapy treatment. Bycutting down on the amount of light from the light emitter to which thecare provider may be exposed, there will be less stress on the careprovider caused by light exposure.

SUMMARY OF THE INVENTION

The present invention relates to phototherapy devices including fiberoptic light emitters having optical fiber end portions at one or bothends that receive light from one or more light emitting diodes (LEDs)for transmission of the light to the light emitters for emissiontherefrom.

In accordance with one aspect of the invention, the light from one ormore LEDs is focused on the optical fiber end portions at one or bothends of the light emitters for transmission of the light to the lightemitters.

In accordance with another aspect of the invention, one or more lensesmay be used to focus the light from the LEDs on the optical fiber endportions.

In accordance with another aspect of the invention, the LEDs may bemounted on a heat sink to dissipate any excess heat generated by theLEDs.

In accordance with another aspect of the invention, the optical fiberend portions may be randomly mixed together and separated into aplurality of groups of end portions that receive light from a pluralityof LEDs to provide a more uniform light output distribution from thelight emitters.

In accordance with another aspect of the invention, the optical fiberend portions of different segments or areas of fiber optic lightemitters may be grouped together in different groups and lighted bydifferent light sources that may be selectively lighted for selectivelylighting one or more of the segments or areas of the light emitters atthe same or different times as desired.

In accordance with another aspect of the invention, LEDs havingdifferent bands of light may be focused on the same or different groupsof optical fiber end portions of fiber optic light emitters.

In accordance with another aspect of the invention, the fiber opticlight emitters may have optical fiber end portions extending from bothends of the light emitters that are mixed together for lighting bothends using one or more light sources.

In accordance with another aspect of the invention, the amount of powerapplied to the LEDs may be increased in accordance with a preprogrammedpower curve based on an average life curve of the LEDs as the LEDs ageover time or in response to a decrease in the light output from the LEDsto maintain a substantially constant light output from the LEDs overtime.

These and other objects, advantages, features and aspects of the presentinvention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter more fully described andparticularly pointed out in the claims, the following description andthe annexed drawings setting forth in detail certain illustrativeembodiments of the invention, these being indicative, however, of butseveral of the various ways in which the principles of the invention maybe employed.

BRIEF DESCRIPTION OF THE DRAWINGS

In the annexed drawings:

FIG. 1 is a schematic top plan view, partly in section, of one form offiber optic phototherapy device of the present invention;

FIGS. 2-5, 7 and 8 are schematic top plan views, partly in section, ofother forms of fiber optic phototherapy devices of the presentinvention;

FIG. 6 is a schematic fragmentary longitudinal section showing one formof fiber optic light emitter of the fiber optic phototherapy devices ofthe present invention;

FIG. 9 is a schematic diagram of an average life curve of a populationof light emitting diodes (LEDs); and

FIG. 10 is a schematic diagram of a preprogrammed power curve based onthe average life curve of the LEDs of FIG. 9 that is used to increasethe power to the LEDs as the LEDs age over time.

DETAILED DESCRIPTION OF THE INVENTION

Referring now in detail to the drawings, and initially to FIG. 1, thereis shown one form of phototherapy device 1 in accordance with thisinvention for use during phototherapy treatment of a patient including afiber optic light emitting member 2 having one or more layers 3 ofindividual optical fibers 4 arranged in close proximity to each other.Each optical fiber includes a light transmitting core portion of asuitably optically transparent material and an outer sheath of a secondoptically transparent material having a different index of refractionthan the core material to prevent the escape of light along its length.The core material may either be made of glass or plastic or amulti-strand filament having the desired optical characteristics. Theouter sheath material is also optically transparent, but because itsindex of refraction is different than that of the core material,substantially total internal reflection is obtained at the sheath-coreinterface, as well known in the art.

Optical fibers 4 may extend beyond one or both ends of light emitter 2where they may be bundled into one or more groups of optical fiber endportions 5 to form one or more light cables 6 for transmitting lightfrom a remote light source 7 to the light emitter as describedhereafter. In FIG. 1 the optical fibers are shown extending outwardlybeyond one end only of the light emitter and bundled together to form asingle light cable 6. At the outermost end of the light cable 6 is aconnector assembly 8 which may consist of a suitable buffer material 9surrounding the gathered optical fiber end portions and a ferrule 10crimped onto the buffer material which squeezes the buffer material andpacks the optical fiber end portions substantially solid.

Light emitter 2 is generally in the shape of a relatively thin lightpanel 11 having a greater width than thickness and opposite ends andsides and top and bottom surfaces, giving the light emitter increasedflexibility. The light emitting surface 12 of the light panel 11 istypically larger than the cross-sectional area of the light cable toreduce energy density by spreading the light over a larger surface areaat the light emitting surface.

A protective cover 15 made of a suitable flexible translucent ortransparent material may surround the light emitter. Also a protectivesleeve 16 made of a suitable flexible opaque or reflective material maysurround light cable 6 for easy maneuverability to facilitate connectionof the connector assembly 8 or other suitable attachment device at theouter end of the light cable to a remote light source 7 for transmissionof the light through the light cable to the light emitter in a mannerwell known in the art. Suitable filters (not shown) may also beinterposed between the light receiving end of the light cable and lightsource 7 to filter out any undesired frequencies of light, for example,infrared or ultraviolet, allowing only those light frequencies desiredto pass through the light cable.

To cause light that is transmitted to light emitter 2 by light cable 6to be emitted from the light emitter, the cladding on the outer surfaceof the optical fibers may be disrupted as by marring, abrading,scratching or otherwise causing mechanical, chemical or otherdisruptions at one or more areas along the length and width of the lightemitter. The amount of light emitted at these locations is a function ofthe depth, size and/or frequency of such disruptions. For example, ifthe disruptions on the outer surface of the optical fibers are madelarger and/or deeper and/or closer together as the distance from thelight receiving end of the light emitter increases, there will be moreuniform emission of light from the light emitter.

A suitable back reflector (shown at 17 in FIG. 6), made for example ofMylar or other suitable light reflective material, may be adhered to theback side of the light emitter for reflecting any light directed towardthe back side back out the front side to provide illumination duringphototherapy treatment.

Light source 7 may comprise one or more light emitting diodes (LEDs) 18(including organic light emitting diodes (OLEDs) and poly light emittingdiodes (PLEDs)) suitably mounted inside a housing 19. Light from theLEDs is focused on the outermost ends of light cables 6 whose connectors8 extend into the housing through one or more openings 20 in thehousing. FIG. 1 shows one such LED 18 mounted inside housing 19 with itslight focused on the outermost end portion of one light cable 6extending into the housing through opening 20 in alignment with the LED,whereas FIG. 2 shows two such LEDs 18 for end lighting two light cables6 extending into the housing.

The actual number of LEDs 18 within a given light source 7 may varydepending on the particular wattage output of the LEDs and the desiredamount of light output to be emitted from the light emitter 2 per unitlight emitting surface area 12. A quarter inch diameter connector typeferrule 10, which is typically used to bundle together 400 optical fiberend portions, is optimum for focusing light from an LED light sourceonto such bundled optical fiber end portions. If one watt LEDs are usedas the light source, it has been found that twelve such LEDs can providea unit area light output from a light emitter comprised of 4800 opticalfibers that is equivalent to that produced using a 120 watt halogen lamplight source. Twelve such LEDs can optimally light 4800 optical fibers,e.g., 400 optical fiber end portions crimped together in each of twelveferrule type connectors. Of course, if higher wattage LEDs are used asthe light source, for example three watt LEDs instead of one watt LEDs,the number of LEDs needed to produce the same unit area light outputwould be considerably less.

From this it is apparent that it is much more efficient to use smallLEDs as the light source instead of a single high wattage light sourcesuch as a halogen lamp. Also LEDs are much longer lasting than highwattage light sources, and have a more useful blue light band width forphototherapy treatment than high voltage light sources. Further, LEDlight sources do not require a fan to cool the light sources as do highwattage light sources, thus eliminating the noisiness of a fan duringuse and allowing the light source to be made much smaller than lightsources using high wattage light sources. At most all that may be neededto dissipate any excess heat generated by the LEDs would be to mount theLEDs to a heat sink 21 which may be attached to the back side of thehousing and may have fins 22 protruding therefrom to further dissipatethe heat as schematically shown in the majority of the drawing figures.

Higher wattage LEDs, up to five watts each, are also available for useas a light source. However, these higher wattage LEDs have a wider lightdispersion angle, making them more difficult to focus the light on theoutermost ends of the optical fiber light cables.

The optical fiber end portions 5 at one or both ends of a fiber opticlight emitter 2 may be separated into more than one group 23 of endportions with the end portions of each group tightly secured together byferrule type connectors 8 tightly surrounding the end portions of therespective groups for receiving light from one or more LEDs 18 asschematically shown in FIG. 2. Also the optical fiber end portions of agiven light emitter 2 may be randomly mixed together prior to beingseparated into a plurality of groups 23 of optical fiber end portions asschematically shown in FIG. 4 to provide a more uniform light outputdistribution from the light emitter.

Further, the optical fiber end portions of different segments 24 of alight emitter 2 may each be grouped together in different groups 23 andthe groups of optical fiber end portions for the different segmentslighted by different LEDs 18 as schematically shown in FIG. 5 forselectively lighting any or all of the segments 24 of the light emitterat the same or different times as desired.

The advantage in being able to selectively light different segments orareas 24 of a fiber optic light emitter 2 is that it allows differentsegments of the light emitter to be turned off if not needed or if lightis being wasted because of the relatively small surface area of apatient being subjected to phototherapy. Not only does this save onpower, it also reduces the amount of light to which care providers maybe exposed. Some individuals are very sensitive to certain bands oflight, particularly blue bands which are especially effective forphototherapy. By cutting down on the amount of light from the lightemitter that can be seen by the care provider, for example, when aninfant receiving phototherapy treatment is placed on a relativelylarge/wide light emitter, there will be less stress on the care providerdue to light exposure. Also the light output from LEDs 18 havingdifferent bands of light may be mixed with LEDs 18 having blue lightbands in an attempt to reduce its effect on making some people nauseous.

Suitable lenses may also be used to focus the light from one or moreLEDs onto the outermost ends of the optical fiber light cables. FIGS. 1and 2 schematically show lenses 25 for focusing light from a singlelight source onto one or more groups 23 of optical fiber end portions ofa single light cable 6. Also, a multi-faceted lens 26 may be used tofocus light from two or more LEDs 18 onto the optical fiber end portionsof a single light cable 6 as schematically shown in FIG. 3.

To increase the unit area light output from a given fiber optic lightemitter, the light emitter may include plural layers 3 of optical fibers4 as schematically shown in FIG. 6. Also the optical fibers 4 in eachlayer may have end portions 5 that are mixed together and grouped withthe end portions of other layers as further schematically shown in FIG.6 for producing a more uniform light output distribution from the lightemitter. Further, the light emitters 2 may have fiber optic end portionsextending from both ends of the light emitters that may be separatedinto a plurality of groups 23 of end portions and tightly securedtogether by ferrule type connectors 8 surrounding the fiber optic endportions of the respective groups for lighting by different LEDs 18 atboth ends of the light emitter as schematically shown in FIG. 7.Alternatively, the optical fiber end portions at one end of the lightemitter may be looped back and mixed with the optical fiber end portionsat the other end of the light emitter for lighting both ends of thelight emitter using the same LEDs 18 as schematically shown in FIG. 8.

Over time the light output of the LEDs diminishes. To provide a moreconstant light output from a light emitter 2 over a longer period oftime using LEDs as the light source, a feedback loop 30, schematicallyshown in FIG. 2, may be employed that includes a photocell 31 thatdetects the light output from the LEDs, and a circuit 32 that increasesthe power to the LEDs with decreased light output to maintain asubstantially constant light output. The photocell 31 may be set up todetect stray light from the LEDs as schematically shown in FIG. 2 whichis proportional to the light output from the LEDs. Alternatively, apreprogrammed power curve schematically shown in FIG. 10 based on anaverage light curve of the LEDs schematically shown in FIG. 9 may beused to increase the power (e.g., current) to the LEDs as the LEDs ageover time.

Although the invention has been shown and described with respect tocertain embodiments, it is obvious that equivalent alterations andmodifications will occur to others skilled in the art upon the readingand understanding of the specification. In particular, with regard tothe various functions performed by the above-described components, theterms (including any reference to a “means”) used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent) even though notstructurally equivalent to the disclosed component which performs thefunctions in the herein exemplary embodiments of the invention. Inaddition, while a particular feature of the invention may have beendisclosed with respect to only one embodiment, such feature may becombined with one or more other features of other embodiments as may bedesired or advantageous for any given or particular application.

1. A phototherapy device for phototherapy treatment of a patientcomprising a light emitter for emitting light, the light emittercomprising one or more layers of optical fibers, the optical fibershaving end portions extending from at least one end of the lightemitter, the end portions being tightly secured together, and at leastone light emitting diode (LED) for focusing light on the end portionsfor transmission of the light to the light emitter for emissiontherefrom, wherein the at least one LED is inside a housing and ismounted to a heat sink attached to a back side of the housing todissipate any excess heat generated by the at least one LED inside thehousing.
 2. The device of claim 1 further comprising a lens for focusinglight from the at least one LED on the end portions.
 3. The device ofclaim 1 wherein the light emitter includes a plurality of layers ofoptical fibers, the optical fibers of each layer having end portionsthat are mixed together and grouped with the end portions of otherlayers for producing a more uniform light output distribution from thelight emitter.
 4. The device of claim 1 wherein the optical fibers haveend portions extending from both ends of the light emitter, anddifferent light sources light the end portions at both ends of the lightemitter.
 5. The device of claim 1 further comprising fins protrudingfrom the heat sink outwardly from the housing to further dissipate anyexcess heat generated by the at least one LED inside the housing.
 6. Thedevice of claim 1 wherein the optical fibers have end portions extendingfrom both ends of the light emitter that are mixed together for lightingboth ends of the light emitter using the same light source or lightsources.
 7. The device of claim 6 wherein a plurality of LEDs are usedto light at least one group of mixed end portions of both ends of thelight emitter.
 8. The device of claim 6 wherein the end portions of bothends of the light emitter are randomly mixed together for producing amore uniform light output distribution from the light emitter.
 9. Thedevice of claim 1 wherein the light emitter has a greater width thanthickness and is surrounded by a translucent or transparent protectivecover.
 10. The device of claim 1 wherein there are a plurality of LEDsfor focusing light on the end portions, the light output of at least oneof the LEDs having blue light bands, and the light output of at leastone other LED having other color light bands that are selectively mixedwith the blue light bands.
 11. A phototherapy device for phototherapytreatment of a patient comprising a light emitter for emitting light,the light emitter comprising one or more layers of optical fibers, theoptical fibers having end portions extending from at least one end ofthe light emitter, the end portions being tightly secured together, aplurality of light emitting diodes (LEDs) inside a housing for focusinglight on the end portions for transmission of the light to the lightemitter for emission therefrom, and a single multi-faceted lens insidethe housing in close proximity to two or more LEDs for focusing lightfrom the two or more LEDs onto the end portions.
 12. The device of claim11 wherein the LEDs are mounted to one or more heat sinks attached to aback side of the housing to dissipate any excess heat generated by theLEDs inside the housing.
 13. The device of claim 12 further comprisingfins protruding from the one or more heat sinks outwardly of the housingto further dissipate any excess heat generated by the LEDs inside thehousing.
 14. A phototherapy device for phototherapy treatment of apatient comprising a light emitter for emitting light, the light emittercomprising one or more layers of optical fibers, the optical fibershaving end portions extending from at least one end of the lightemitter, the end portions being tightly secured together, and at leastone light emitting diode (LED) for focusing light on the end portionsfor transmission of the light to the light emitter for emissiontherefrom, the LED being mounted to a heat sink, and means forincreasing the amount of power to a plurality of LEDs in response to adecrease in the light output from the LEDs to maintain a substantiallyconstant light output from the LEDs.
 15. The device of claim 14 whereinthe means for increasing the amount of power to the LEDs comprises aphotocell that detects light from the light source, and a circuit thatincreases the power to the LEDs as the light output from the LEDsdecreases.
 16. The device of claim 14 wherein the photocell detectsstray light from the LEDs which is proportional to the light output fromthe LEDs.
 17. A phototherapy device for phototherapy treatment of apatient comprising a light emitter for emitting light, the light emittercomprising one or more layers of optical fibers, the optical fibershaving end portions extending from at least one end of the lightemitter, the end portions being tightly secured together, and at leastone light emitting diode (LED) for focusing light on the end portionsfor transmission of the light to the light emitter for emissiontherefrom, the LED being mounted to a heat sink, and a preprogrammedpower curve based on an average life curve of a plurality of LEDs thatis used to increase the power to the LEDs as the LEDs age over time.